Methods and apparatus related to link establishment in a wireless backhaul network

Abstract

Various aspects related to using cellular RATs and/or features thereof for backhauling purposes are described. In an aspect, a solution to enable synchronization and establishing links among the ANs using available RATs with minimum modifications is provided. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus for wireless communication are provided. The apparatus maybe a first AN, e.g., base station. The apparatus maybe configured to determine a synchronization schedule of at least one second AN based on received information indicating the synchronization schedule of the at least one second AN, and transmit information regarding the synchronization schedule of the at least one second AN to at least one of one or more neighboring ANs or one or more UEs.

What is claimed is: 
     
       1. A method of wireless communication of a first access node (AN), comprising:
 determining a synchronization schedule of at least one second AN based on received synchronization information regarding the synchronization schedule of the at least one second AN, the synchronization schedule of the at least one second AN indicating a pattern of synchronization operations associated with a first set of synchronization signal (SS) burst sets and a second set of SS burst sets, the first set of SS burst sets associated with facilitating synchronization with one or more user equipment (UEs) and the second set of SS burst sets associated with facilitating synchronization with one or more neighboring ANs,
 wherein the first set of SS burst sets is associated with a first transmission configuration including at least one of a first set of beams, first constituent signals, and a first bandwidth allocation, and 
 the second set of SS burst sets is associated with a second transmission configuration including at least one of a second set of beams, second constituent signals, and a second bandwidth allocation, 
 the second transmission configuration being different from the first transmission configuration based on at least one of
 the second set of beams comprising different beams than the first set of beams, 
 the second constituent signals comprising different signals than the first constituent signals, and 
 the second bandwidth allocation comprising a wider bandwidth allocation than the first bandwidth allocation; and 
 
 
 transmitting the synchronization information regarding the synchronization schedule of the at least one second AN to at least one of the one or more neighboring ANs or the one or more UEs. 
 
     
     
       2. The method of  claim 1 , wherein the synchronization information regarding the synchronization schedule includes at least one of a single bit indicating that the at least one second AN is participating in backhaul synchronization in a backhaul network, a first set of bits indicating the synchronization schedule of the at least one second AN, or a second set of bits to indicate changes in the synchronization schedule and future states of the at least one second AN. 
     
     
       3. The method of  claim 2 , wherein the first set of bits comprises a random seed that can be used to determine the synchronization schedule of the at least one second AN, or an index to a preconfigured list of synchronization schedules, and wherein the index comprises a hop-count or a color-code. 
     
     
       4. The method of  claim 1 , wherein the synchronization information regarding the synchronization schedule is transmitted in one or more of a master information block (MIB), a system information block (SIB), or a radio resource control (RRC) message. 
     
     
       5. The method of  claim 1 , wherein the first AN receives the synchronization information regarding the synchronization schedule of the at least one second AN from one of the at least one second AN, a set of neighboring ANs, a core network node, or a UE. 
     
     
       6. The method of  claim 1 , wherein the synchronization schedule of the at least one second AN indicates a set of modes of the at least one second AN during the second set of SS burst sets. 
     
     
       7. The method of  claim 6 , wherein the set of modes of the at least one second AN includes one of a reception mode, a transmission mode, a hybrid mode, a non-synchronization mode, or an idle mode. 
     
     
       8. The method of  claim 1 , further comprising:
 transmitting information regarding a synchronization schedule of the first AN to at least one of the one or more neighboring ANs or the one or more UEs. 
 
     
     
       9. The method of  claim 8 , further comprising determining the synchronization schedule of the first AN based on one or more of information received from a set of ANs, a set of preconfigured system parameters, network configuration information received from upper layers, or a random seed. 
     
     
       10. The method of  claim 9 , wherein the information received from the set of ANs includes the synchronization information regarding the synchronization schedule of the at least one second AN. 
     
     
       11. A first access node (AN), comprising:
 means for determining a synchronization schedule of at least one second AN based on received synchronization information regarding the synchronization schedule of the at least one second AN, the synchronization schedule of the at least one second AN indicating a pattern of synchronization operations associated with a first set of synchronization signal (SS) burst sets and a second set of SS burst sets, the first set of SS burst sets associated with facilitating synchronization with one or more user equipment (UEs) and the second set of SS burst sets associated with facilitating synchronization with one or more neighboring ANs,
 wherein the first set of SS burst sets is associated with a first transmission configuration including at least one of a first set of beams, first constituent signals, and a first bandwidth allocation, and 
 the second set of SS burst sets is associated with a second transmission configuration including at least one of a second set of beams, second constituent signals, and a second bandwidth allocation, 
 the second transmission configuration being different from the first transmission configuration based on at least one of 
 the second set of beams comprising different beams than the first set of beams,
 the second constituent signals comprising different signals than the first constituent signals, and 
 the second bandwidth allocation comprising a wider bandwidth allocation than the first bandwidth allocation; and 
 
 
 means for transmitting the synchronization information regarding the synchronization schedule of the at least one second AN to at least one of the one or more neighboring ANs or the one or more UEs. 
 
     
     
       12. The first AN of  claim 11 , wherein the synchronization information regarding the synchronization schedule includes at least one of a single bit indicating that the at least one second AN is participating in backhaul synchronization in a backhaul network, a first set of bits indicating the synchronization schedule of the at least one second AN, or a second set of bits to indicate changes in the synchronization schedule and future states of the at least one second AN. 
     
     
       13. The first AN of  claim 12 , wherein the first set of bits comprises a random seed that can be used to determine the synchronization schedule or an index to a preconfigured list of synchronization schedules, and wherein the index comprises a hop-count or a color-code. 
     
     
       14. The first AN of  claim 11 , wherein the synchronization schedule of the at least one second AN indicates a set of modes of the at least one second AN during the second set of SS burst sets. 
     
     
       15. The first AN of  claim 14 , wherein the set of modes of the at least one second AN includes one of a reception mode, a transmission mode, a hybrid mode, a non-synchronization mode, or an idle mode. 
     
     
       16. The first AN of  claim 11 , wherein the means for transmitting is further configured to transmit information regarding a synchronization schedule of the first AN to at least one of the one or more neighboring ANs or the one or more UEs. 
     
     
       17. A first access node (AN) for wireless communication, comprising:
 a memory; and 
 at least one processor coupled to the memory and configured to:
 determine a synchronization schedule of at least one second AN based on received synchronization information regarding the synchronization schedule of the at least one second AN, the synchronization schedule of the at least one second AN indicating a pattern of synchronization operations associated with a first set of synchronization signal (SS) burst sets and a second set of SS burst sets, the first set of SS burst sets associated with facilitating synchronization with one or more user equipment (UEs) and the second set of SS burst sets associated with facilitating synchronization with one or more neighboring ANs,
 wherein the first set of SS burst sets is associated with a first transmission configuration including at least one of a first set of beams, first constituent signals, and a first bandwidth allocation, and 
 the second set of SS burst sets is associated with a second transmission configuration including at least one of a second set of beams, second constituent signals, and a second bandwidth allocation, 
 the second transmission configuration being different from the first transmission configuration based on at least one of
 the second set of beams comprising different beams than the first set of beams, 
 the second constituent signals comprising different signals than the first constituent signals, and 
 the second bandwidth allocation comprising a wider bandwidth allocation than the first bandwidth allocation; and 
 
 
 transmit the synchronization information regarding the synchronization schedule of the at least one second AN to at least one of the one or more neighboring ANs or the one or more UEs. 
 
 
     
     
       18. The first AN of  claim 17 , wherein the synchronization information regarding the synchronization schedule includes at least one of a single bit indicating that the at least one second AN is participating in backhaul synchronization in a backhaul network, a first set of bits indicating the synchronization schedule of the at least one second AN, or a second set of bits to indicate changes in the synchronization schedule and future states of the at least one second AN. 
     
     
       19. The first AN of  claim 18 , wherein the first set of bits comprises a random seed that can be used to determine the synchronization schedule or an index to a preconfigured list of synchronization schedules, and wherein the index comprises a hop-count or a color-code. 
     
     
       20. The first AN of  claim 17 , wherein the synchronization schedule of the at least one second AN indicates a set of modes of the at least one second AN during the second set of SS burst sets. 
     
     
       21. The first AN of  claim 17 , wherein the at least one processor is further configured to transmit information regarding a synchronization schedule of the first AN to at least one of the one or more neighboring ANs or the one or more UEs. 
     
     
       22. The first AN of  claim 21 , wherein the at least one processor is further configured to determine the synchronization schedule of the first AN based on one or more of information received from a set of ANs, a set of preconfigured system parameters, network configuration information received from upper layers, or a random seed. 
     
     
       23. A method of wireless communication at an access node, wherein the access node is a member of a first access node group of a network of access nodes, the method comprising:
 during a first set of synchronization resources, transmitting synchronization signals for downlink synchronization; and 
 during a second different set of synchronization resources, performing access node backhaul synchronization as part of the first access node group, wherein performing the access node backhaul synchronization as part of the first access node group comprises:
 at a first time interval, receiving first signals from one or more access nodes included in a second different access node group of the network of access nodes; 
 using the first signals from the one or more access nodes included in the second different access node group to update synchronization of the access node with the one or more access nodes of the network of access nodes; and 
 at a second time interval, transmitting second signals to access nodes included in at least the second different access node group, the second signals including synchronization information,
 wherein transmitting the synchronization signals for the downlink synchronization is based on a first transmission configuration including at least one of a first set of beams, first constituent signals, and a first bandwidth allocation, and 
 transmitting the second signals to the access nodes is based on a second transmission configuration including at least one of a second set of beams, second constituent signals, and a second bandwidth allocation, 
 the second transmission configuration being different from the first transmission configuration based on at least one of
 the second set of beams comprising different beams than the first set of beams, 
 the second constituent signals comprising different signals than the first constituent signals, and 
 the second bandwidth allocation comprising a wider bandwidth allocation than the first bandwidth allocation. 
 
 
 
 
     
     
       24. The method of  claim 23 , wherein the second different set of synchronization resources includes a first subframe, and the first time interval and the second time interval are included in the first subframe. 
     
     
       25. The method of  claim 23 , wherein the first transmission configuration comprises a first configuration of transmission beams with a first elevation angle and a first azimuth angle sweep pattern, and the second transmission configuration comprises a second configuration of beams with a second elevation angle and a second azimuth angle sweep pattern, wherein the second elevation angle, the second azimuth angle sweep pattern, or both are different than the first elevation angle and the first azimuth angle sweep pattern. 
     
     
       26. The method of  claim 23 , wherein transmitting synchronization signals according to the second transmission configuration comprises transmitting a synchronization signal with at least one difference in one or more of a primary synchronization signal (PSS), secondary synchronization signal (SSS), extended service set (ESS), or physical broadcast channel (PBCH). 
     
     
       27. The method of  claim 23 , further comprising:
 transmitting synchronization information indicative of a synchronization schedule of at least one of the access node, or at least one different access node of the network of access nodes. 
 
     
     
       28. The method of  claim 27 , wherein the synchronization information indicative of the synchronization schedule of the access node comprises a first set of bits indicating the second different set of synchronization resources used for performing the access node backhaul synchronization, the second different set of synchronization resources recurring periodically. 
     
     
       29. The method of  claim 28 , wherein the synchronization information indicative of the synchronization schedule of the access node further comprises a bitmap indicating a state of the access node within each of a plurality of different portions of a resource of the second different set of synchronization resources recurring periodically, a first bit of the bitmap indicating a first state of the access node within a first portion of the resource and a second bit of the bitmap indicating a second state of the access node within a second portion of the resource, wherein the first portion and the second portion of the resource are non-overlapping. 
     
     
       30. The method of  claim 29 , wherein the resource comprises a set of one or more consecutive subframes, and wherein the first portion of the resource is the first time interval and the second portion of the resource is the second time interval. 
     
     
       31. The method of  claim 28 , wherein the synchronization information indicative of the synchronization schedule of the access node further comprises a set of bits indicating a state of the access node within each different resource of the second different set of synchronization resources. 
     
     
       32. The method of  claim 31 ,
 wherein the state of the access node within a resource remains a same state; 
 wherein the state of the access node within the resource and the resource recurs periodically; and 
 wherein each resource of the second different set of synchronization resources includes a set of one or more consecutive subframes. 
 
     
     
       33. The method of  claim 27 , wherein the synchronization information indicative of the synchronization schedule of the at least one different access node comprises a first set of bits indicating a third set of synchronization resources used by the at least one different access node for performing the access node backhaul synchronization, the third set of synchronization resources recurring periodically. 
     
     
       34. The method of  claim 33 , wherein the synchronization information indicative of the synchronization schedule of the at least one different access node further comprises a bitmap indicating a state of the at least one different access node within each of a plurality of different portions of a resource of the third set of synchronization resources recurring periodically, a first bit of the bitmap indicating a first state of the at least one different access node within a first portion of the resource and a second bit of the bitmap indicating a second state of the at least one different access node within a second portion of the resource, wherein the first portion and the second portion of the resource are non-overlapping. 
     
     
       35. The method of  claim 1 , wherein the first transmission configuration includes a first combination of two or more of the first set of beams, the first constituent signals, and the first bandwidth allocation, and the second transmission configuration includes a second combination of two or more of the second set of beams, the second constituent signals, and the second bandwidth allocation. 
     
     
       36. The method of  claim 1 , wherein the first transmission configuration includes the first set of beams, the first constituent signals, and the first bandwidth allocation, and the second transmission configuration includes the second set of beams, the second constituent signals, and the second bandwidth allocation.